Removing entry(s) from JSON array based on key/value

Damn, forget about jQuery! This is a pure javascript task.

• To loop through an Array, use for (var i=0; i<array.length; i++), to loop over an Object use for (var i in object)
• To delete an array entry, use splice(). To delete an object attribute, use delete object[key];.
• To filter an Array, in modern javascript versions you can use filter() with a callback function for every entry; it creates a new Array. There is no such (native) method for objects.

You may find some libraries with helpful utility functions, like underscore. But to learn JS, it may be better to do it with native methods first.

Underscore.js is the library to use for all things data. Functions that will be useful for your data are; each, reject and groupBy.

If you don't want to write the code directly to do the operations you want, you can use a library like underscore.js which packages up a lot of handy functions for manipulating collections. So after you've parsed your JSON, you could, for example, use reject() to filter out a specific object in your collection.

I believe the following code does roughly what you're asking for. Check out the working fiddle: http://jsfiddle.net/pUhDR/3/ By the way, I agree with @Gazler, you could use the underscore library, it's more high level and easier to read than this:

var countriesString = JSON.stringify([{
    "Country": "Spain",
    "info info1": 0.329235716,
    "info info2": 0.447683684,
    "info info3": 0.447683747
}, {
    "Country": "Chile",
    "info info1": 1.302673893,
    "info info2": 1.357820775,
    "info info3": 1.35626442
}, {
    "Country": "USA",
    "info info1": 7.78805016,
    "info info2": 26.59681951,
    "info info3": 9.200900779
}]);

var countries = JSON.parse(countriesString);

// create new array
var newCountriesArray = new Array();
// exclude some countries
var excludeCountries = new Object();
excludeCountries['Spain'] = true;
// rename some countries
var renameCountries = new Object();
renameCountries['USA'] = 'United States of America';

for (index in countries) {
    if (countries[index].Country in renameCountries) {
        countries[index].Country = renameCountries[countries[index].Country];
    }
    if (!(countries[index].Country in excludeCountries)) {
        newCountriesArray.push(countries[index]);
    }
}

alert(JSON.stringify(newCountriesArray));

As we have to delete some indexes in the collection we are currently iterate I choose to invert iteration like this :

const fields = [{key: "entry1",},{key: "entry2",},{key: "entry3",},{key: "entry4",},{key: "entry5",},]

const arrToDelete = ['entry3', 'entry4']
for (let idx = fields.length - 1; idx >= 0; idx--) {
  if (arrToDelete.includes(fields[idx].key)){
    fields.splice(idx, 1);
  }
}

You can use delete operator on the array and delete the element.

1. Create a list of items you wanted to delete. In below case 'Chile'
2. Iterate over the list and delete the items

DEMO

Code:

var toRemove = [];
$.each(output_json, function(i) {
  $.each(this, function(k, v) {
    if (v == 'Chile') toRemove.push(i);
  });
});

//remove all marked
for (var i = 0; i < toRemove.length; i++) {
    delete output_json[toRemove[i]];
}